Marine safety device attachment with automatic release capability

ABSTRACT

A device for fastening emergency equipment to a vessel includes a hydrostatic release mechanism, a tether, and a float-free link. The tether is attached to the hydrostatic release mechanism and provides an attachment point for lashing the emergency equipment to the vessel. The tether may also be threaded through openings in the curved partially tubular body of the float-free link. A breakable bridge is integrally coupled to the body of the float-free link to form a closed loop. The breakable bridge is designed to be the break point when the emergency equipment needs to be freed from a vessel that has sunk below a predetermined depth. When the vessel sinks below the predetermined depth, the hydrostatic release mechanism severs the tether thus freeing the emergency equipment from one point of attachment to the vessel. The bridge is designed to break when the strain on the fastening line, e.g., the painter line, is between a predetermined minimum force and maximum force.

BACKGROUND

Chapter 1 of Title 46 of the Code of Federal Regulations (46 C.F.R.)governs marine safety as enforced by the Coast Guard. Vessels arerequired to pass inspection and maintain a Certificate of Inspection,which describes the vessel, the manning requirements, and the safetyequipment and appliances required to be on board, among other things.See 46 C.F.R. §2.01-5. Safety equipment includes such things as survivalcrafts (e.g., lifeboats or life rafts), emergency position indicatingradio beacons (EPIRB), and life buoys. The regulations require lifeboatsor life rafts on a vessel to do two things: float free and automaticallyinflate if the vessel sinks. 46 C.F.R. §180.130. Similar behavior isneeded from EPIRBs, life buoys and other types of marine emergencysafety equipment. See, for example, 46 C.F.R. §180.64.

SUMMARY

A float-free link for use in fastening emergency equipment to a vesselis described. In one example embodiment, the float-free link has firstlinkage means for allowing a first fastener to be attached thereto,second linkage means for allowing a second fastener to be attachedthereto, threading means for allowing a third fastener to be threadedthrough a portion of both the first and second linkage means, andbreakaway means for controlled breaking of the float-free link between aspecified minimum and a specified maximum force.

As a further example, the first linkage means may be a first closed loophaving a first aperture through which the first fastener may be attachedto the first closed link. The second linkage means may be a second loopintegrally coupled to the first closed loop. The second loop has asecond aperture through which the second fastener may be attached to thesecond loop. The threading means may be continuous channel extendingaround at least a portion of the first aperture and a portion of thesecond aperture, to allow the third fastener, for example, a rope, acord, cable or wire to be threaded through the channel. The breakawaymeans may be a breakaway bridge that is integrally connected to thesecond loop to form a closed loop. The breakaway bridge may be thedesigned break point in the float-free link. To accomplish thatfunction, the breakaway bridge has a tensile strength that is less thanthat of either the first link or the second link. Furthermore, thebreakaway bridge needs to break when a specified force is applied.

The float-free link may be used in combination with a hydrostaticrelease mechanism to provide a hydrostatically-releasable device thatmay be used to fasten an emergency device to a vessel. The hydrostaticrelease mechanism may be attached to a tether that is configured tomechanically couple the emergency device to the vessel. The hydrostaticrelease mechanism may be configured to sever the tether in an emergency,e.g., when the hydrostatic release mechanism is submerged below apredetermined depth. A first external fastener may be mechanicallycoupled both to the vessel and to the float-free link by way ofattachment to the link through a first aperture in the link. A secondexternal fastener may be mechanically coupled to the emergency deviceand to the float-free link by way of attachment to the link through thesame aperture in the link or through a second aperture in the link Achannel through which the tether may be threaded may be provided in thebody of the float-free link. A breakaway bridge may be integrally formedin the float-free link and may be configured to break when the strainexerted by the second external fastener, after the tether has beensevered, exceeds the tensile strength of the bridge.

In another example embodiment, a float free link may be provided. Thefloat free link may include a first closed loop including a firstaperture configured to receive a first fastener therethrough; a secondloop integrally coupled to the first closed loop, the second loop havingfirst and second ends and including a second aperture configured toreceive a second fastener therethrough; a channel extending around atleast a portion of the first aperture, said channel configured toreceive a third fastener therein; and a breakaway bridge connecting thefirst and second ends of the second loop to form a closed loop, whereinthe bridge is designed to break between a minimum and a maximum strainforce exerted on the link by the first and second fastener and whereinthe bridge is substantially weaker in tensile strength than the firstloop and the second loop.

Optionally, the float-free link may have at least a partial toroidalconfiguration. The float-free link may be unitary integrally moldedstructure, which may be composed of a plastic material that issubstantially stable to ultraviolet light, such as a polycarbonateplastic. In one alternative configuration, the minimum force needed tobreak the link is at least 100 lbs and the maximum force but no morethan 134 lbs. In a second alternative configuration, the minimum forceis at least 200 lbs and the maximum force is no more than 268 lbs. In athird alternative configuration the minimum force is at least 400 lbsand the maximum force is no more than 536 lbs. These ranges maycorrespond to different sized pieces of emergency equipment withdifferent buoyancies.

Optionally, the first aperture may be substantially circular and thesecond aperture may be elongated. The channel may extend around at leasta portion of the second loop. Preferably, the channel does not extendaround a portion of the second loop where the breakaway bridge islocated.

Another example embodiment of the present invention is a float free linkhaving a first linkage means for allowing a first fastener to beattached thereto; a second linkage means for allowing a second fastenerto be attached thereto, wherein the second linkage means is integrallycoupled to the first linkage means; a threading means for allowing athird fastener to be threaded through a portion of both the firstlinkage means and the second linkage means; and a breakaway means forcontrolled breaking of the float-free link between a minimum and amaximum force and at a specific location on the float-free link.Optionally, the first linkage means and the second linkage means form aunitary integrally molded structure, which may be composed of a plasticmaterial that is substantially stable to ultraviolet light, such as apolycarbonate. In one variation, the minimum force is at least 100 lbsand the maximum force is no more than 134 lbs. In a second variation theminimum force is at least 200 lbs and the maximum force is no more than268 lbs. In a third variation, the minimum force is at least about 400lbs and the maximum force is no more than about 536 lbs. Optionally, thethreading means extends around at least a portion of the second linkagemeans, although preferably not around the portion of the second linkagemeans where the breakaway means is located.

Another example embodiment of the present invention is ahydrostatically-releasable device for fastening an emergency device to avessel. The example device may include a tether configured tomechanically couple the emergency device to the vessel; a hydrostaticrelease mechanism attached to the tether, the hydrostatic releasemechanism configured to sever the tether when the hydrostatic releasemechanism is submerged below a predetermined depth; a first externalfastener mechanically coupled to the vessel; a second external fastenermechanically coupled to the emergency device; and an integrally formedfloat-free link having a first closed link including a first aperturehaving the first external fastener mechanically coupled thereto; asecond link coupled to the first closed link, the second link havingfirst and second ends and including a second aperture having the secondexternal fastener mechanically coupled thereto; a channel extendingaround at least a portion of the first aperture, said channel having aportion of the tether threaded therethrough; and a breakaway bridgeconnecting the first and second ends of the second link to form a closedloop in the second link, wherein the bridge is designed to break betweena minimum and a maximum force resulting from strain exerted by thesecond external fastener once the tether has been severed by thehydrostatic release mechanism.

Optionally, the float-free link has a hollow tubular body which formsthe channel through which the tether is threaded. The hollow tubularbody may be partially open along its length and may also be toroidal inshape. The breakaway bridge may have a tensile strength substantiallyless than that of the first or second link, which may be achieved have asubstantially reduced cross-section as compared to that of the first orsecond link. More particularly, the breakaway bridge may be dimensionedonly to break after the minimum force has been exceeded and before themaximum force has been exceeded. In one variant, the minimum force iswithin a first range of 100 lbs to 400 lbs and the maximum force iswithin a second range of 134 lbs to 536 lbs, and the minimum force isless than the maximum force. Optionally, the tether may be a rope, wire,webbing, or other sort of attachment mechanism. The hydrostatic releasemechanism may be attached to the tether at a point along the tether thatis outside of the channel of the float-free link.

Another example embodiment of the present invention is ahydrostatically-releasable device for fastening an emergency device to avessel. The device may include a tether configured to mechanicallycouple the emergency device to the vessel; a hydrostatic releasemechanism attached to the tether, the hydrostatic release mechanismconfigured to sever the tether when the hydrostatic release mechanism issubmerged below a predetermined depth; and a first external fastenermechanically coupled to the vessel; a second external fastenermechanically coupled to the emergency device; and an integrally formedfloat-free link having a first linkage means for allowing a firstfastener to be attached thereto; second linkage means for allowing asecond fastener to be attached thereto, wherein the second linkage meansis integrally coupled to the first linkage means; threading means forallowing a portion of the tether to be threaded through a portion of thefirst linkage means; and breakaway means for controlled breaking of thefloat-free link at a specific location on the float-free link andbetween a minimum and a maximum force resulting from strain caused bythe second external fastener once the tether has been severed by thehydrostatic release mechanism.

Another example embodiment of the present invention is a float-freelink. The float free link may include a curved link body having anaperture configured to receive at least one fastener therethrough and achannel extending around at least a portion of the aperture, saidchannel configured to receive a second fastener therein; and a breakawaybridge integrally formed with the curved link body to form a closedloop, wherein the breakaway bridge is designed to break between aminimum and a maximum force and wherein the breakaway bridge issubstantially weaker in tensile strength than the curved link body.Optionally, the channel does not extend around the breakaway bridge. Theaperture may be narrower at a first end and the breakaway bridge may belocated at the first end. The curved link body may have a cross-bar todivide the aperture into first aperture and second aperture, whereineach aperture is configured to receive a fastener therethrough. Thefirst aperture is substantially circular and the second aperture iselongated. The float free link may have at least a partial toroidalconfiguration and may be a unitary integrally molded structure, forexample a plastic material that is substantially stable to ultravioletlight such as nylon or a polycarbonate.

In one variant of the float-free link, the minimum force is at least 100lbs and the maximum force is no more than 134 lbs. In a second variant,the minimum force is at least 200 lbs and the maximum force is no morethan 268 lbs. In a third variant, the minimum force is at least 400 lbsand the maximum force is no more than 536 lbs.

Another example embodiment of the present invention is a float-freelink, having a first linkage means for allowing a first fastener to beattached thereto; threading means for allowing a second fastener to bethreaded through a portion of the linkage means; and breakaway means forcontrolled breaking of the float-free link between a minimum and amaximum force and at a specific location on the float-free link. Thefloat free link may also have second linkage means for allowing a thirdfastener to be attached thereto, wherein the second linkage means isintegrally coupled to the first linkage means. The first linkage meansand the second linkage means may form a unitary integrally moldedstructure, for example from plastic material that is substantiallystable to ultraviolet light, such as nylon or polycarbonate.

In one variant, the minimum force is at least 100 lbs and the maximumforce is no more than 134 lbs. In a second variant the minimum force isat least 200 lbs and the maximum force is no more than 268 lbs. In athird variant, the minimum force is at least 400 lbs and the maximumforce is no more than 536 lbs.

Another example embodiment of the present invention is ahydrostatically-releasable device for fastening an emergency device to avessel. The device includes a tether configured to mechanically couplethe emergency device to the vessel; a hydrostatic release mechanismattached to the tether, the hydrostatic release mechanism configured tosever the tether when the hydrostatic release mechanism is submergedbelow a predetermined depth; a first external fastener mechanicallycoupled to the vessel; a second external fastener mechanically coupledto the emergency device; and an integrally formed float-free link havinga curved link body having at least one aperture configured tomechanically couple the float-free link to the first external fastener,and a channel extending around at least a portion of the at least oneaperture, said channel configured to receive a portion of the tetherthreaded therethrough; and a breakaway bridge integrally formed with thecurved link body to form a closed loop, wherein the breakaway bridge isdesigned to break between a minimum and a maximum force resulting fromstrain exerted by the second external fastener once the tether has beensevered by the hydrostatic release mechanism.

Optionally, the curved link body is partially a hollow tubular bodywhich forms the channel through which the tether is threaded. The hollowtubular body may be partially open along its length and partiallytoroidal in shape. The breakaway bridge may have a tensile strengthsubstantially lower than that of the first or second link and asubstantially reduced cross-section as compared to that of the first orsecond link. The breakaway bridge may be dimensioned only to break afterthe minimum force has been exceeded and before the maximum force hasbeen exceeded.

Optionally, the minimum force is within a first range of about 100 lbsto 400 lbs and the maximum force is within a second range of about 134lbs to 536 lbs, and the minimum force is less than the maximum force. Inone variant, the minimum force is at least 100 lbs and the maximum forceis no more than 134 lbs. In a second variant the minimum force is atleast 200 lbs and the maximum force is no more than 268 lbs. In a thirdvariant the minimum force is at least 400 lbs and the maximum force isno more than 536 lbs.

Optionally, the tether may be a rope, wire, line, webbing or otherattachment. The hydrostatic release mechanism may be attached to thetether at a point along the tether that is outside of the channel of thefloat-free link. The curved link body may have a cross-bar to divide theaperture into first aperture and second aperture, wherein the firstaperture is configured to mechanically couple with the first externalfastener and wherein the second aperture is configured to mechanicallycouple with the second external fastener.

Another example embodiment of the present invention is ahydrostatically-releasable device for fastening an emergency device to avessel. The device may include a tether configured to mechanicallycouple the emergency device to the vessel; a hydrostatic releasemechanism attached to the tether, the hydrostatic release mechanismconfigured to sever the tether when the hydrostatic release mechanism issubmerged below a predetermined depth; and a first external fastenermechanically coupled to the vessel; a second external fastenermechanically coupled to the emergency device; and an integrally formedfloat-free link having linkage means for allowing the first externalfastener to be mechanically coupled thereto; threading means forallowing the tether to be threaded through a portion of the linkagemeans; and breakaway means for controlled breaking of the float-freelink at a specific location on the float-free link and between a minimumforce and a maximum force resulting from strain caused by the secondexternal fastener once the tether has been severed by the hydrostaticrelease mechanism.

Features and advantages of example embodiments of the present inventionwill be apparent from the accompanying drawings and from the detaileddescription that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings in which:

FIG. 1 is an illustration of a hydrostatic release unit, according to anexample embodiment of the invention.

FIG. 2 is a perspective drawing of a first float-free link, according toan example embodiment of the invention.

FIG. 3 is an end view of the float-free link of FIG. 2.

FIG. 4 is a perspective drawing of a second float-free link, accordingto another example embodiment of the invention.

FIG. 5 is a cross-sectional view of the float-free link of FIG. 4.

FIG. 6 is a perspective drawing of a third float-free link, according toanother example embodiment of the invention.

FIG. 7 is a top view of the float-free link of FIG. 6.

FIG. 8 is an illustration of an application of the hydrostatic releaseunit of FIG. 1, according to an example embodiment of the presentinvention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Some example embodiments of the present invention generally relate to adevice for fastening emergency equipment, such as life rafts, life buoysor radio beacons, to a vessel or its deck. The fastening device mayinclude a breakable or float-free link used in combination with otherfasteners, such as ropes, wires, or cable, and a hydrostatic releasemechanism, which is designed to sever a tether securing floatableemergency equipment from a vessel when the vessel is submerged to apredetermined depth. A rope, cable or other fastener may be attached tothe hydrostatic release mechanism and provides an attachment point forlashing the emergency equipment to the vessel. The float-free link maybe a unitary integrally formed tubular link having at least two separateapertures to provide areas of attachment for external fasteners. In someexample embodiments, the float-free link may also include a third placeof attachment, a curved tubular body that may be configured to provide abuilt-in continuous channel through which a rope or other fastener maythread through the tubular body, mechanically coupling the fastener tothe link. The ends of the curved tubular body are connected together viaa breakable bridge. The breakable bridge may be configured to be a breakpoint when the emergency equipment needs to be freed from a vessel thathas sunk below a predetermined depth, e.g., after the tether has beensevered and when the buoyancy of the emergency equipment exertssufficient force on the breakable bridge to cause its failure. While inthe example embodiments, the breakaway bridge is shown at the end point,it will be appreciated that the breakaway bridge could alternatively beplaced at other locations in a float-free link.

In use, the emergency equipment, such as a life raft, may be attached tothe vessel via the tether threaded through the tube. The tether isconfigured so that it may be severed by the hydrostatic releasemechanism in an emergency situation. In addition, the painter line ofthe life raft may be attached via an external fastener, such as ashackle, to one end of the float-free link where the breakaway bridge islocated. The other end of the float-free link is fastened to a strongpoint on the deck of the vessel via another external fastener, typicallya shackle. The tether line may be threaded through the tube and may beattached to the vessel. The tether line may also provide reinforcementat that tubular end of the float-free link to prevent its unintendedbreakage. When the vessel sinks below a certain depth, the hydrostaticrelease mechanism severs the tether line thus freeing the life raft fromone point of attachment to the vessel. The bridge is designed to breakwhen the strain on the painter line is between a predetermined minimumforce and maximum force, thus allowing the emergency equipment or deviceto float free on the water surface instead of being pulled down with thesinking vessel. It will be appreciated that the configuration may bereversed, where the second line securing the float-free link to thevessel may be on the side of the float-free link with the breakablebridge.

One example embodiment of the float-free link is particularly simple tomanufacture and to use because it is a unitary integrally moldedstructure, requiring no assembly. The example float-free link isdesigned to break at a specific location, e.g., a narrowed breakawaybridge, when the strain exerted by the painter line exceeds the yieldstrength of the link at that specific location. Example float-free linksmay have single or multiple apertures configured for various andmultiple fasteners to be attached to the device.

As used herein, the following terms should be understood to have theindicated meanings:

When an item is introduced by “a” or “an,” it should be understood tomean one or more of that item.

“Comprises” means includes but is not limited to.

“Comprising” means including but not limited to.

“Includes” means has but is not limited to.

“Having” means including but not limited to.

“Mechanically coupled” means physically linked either directly orindirectly.

“Integrally formed” means formed as a single body or unit withoutphysically separate subcomponents.

Floatable devices, such as life rafts, life buoys, or emergency radiobeacons are normally secured to a vessel or watercraft by tethers whennot in use. Such floatable devices are designed for use by the crew ofsaid watercraft in an emergency. However, when the crew finds itself ina rapid sinking situation caused by, for example, when the structuralintegrity of the vessel is seriously compromised via a collision withanother vessel or a reef, there may not be enough time to release all ofthe floating emergency equipment on a vessel. Other rapid sinkingscenarios include, but are not limited to, explosions, fire, storms andthe like. In such situations, the crew may find itself in the water withneeded life rafts and emergency radio beacons still attached to the nowsubmerged vessel.

It is therefore a desired safety feature for the floatable devices tobreakaway from the submerged vessel. Marine regulations exist topromulgate safety on vessels. Marine regulations require a life raft todo two things: float free and automatically inflate if the vessel sinks.Some example embodiments of the present invention employ a hydrostaticrelease mechanism. The hydrostatic release mechanism may be configuredto automatically trigger the release of a safety device, such as a liferaft, when the life raft or other safety device submerges below apredetermined depth. For example, the release mechanism may beconfigured to sever a tether or other fastener lashing the life raft tothe railing of the vessel. The life raft then starts to float to thesurface because of its internal buoyancy, which stretches the painterline. Once it is taut, the painter engages a mechanism to inflate thelife raft. After the life raft is inflated, its buoyancy force issupposed to break a float-free link that is connecting the painter lineto the vessel to allow the life raft to float to the surface instead ofbeing pulled down with the sinking vessel. See 46 C.F.R. §160.073.

U.S. Pat. No. 7,302,739, filed Apr. 22, 2003 and entitled “Device forFastening Emergency Equipment to a Ship's Deck” generally describes abreakable device having multiple parts that may be used in attaching anemergency device to a ship's deck. The breakable device includes aplastic shearing link and a sleeve that is snap-fitted onto the shearinglink. A wire having a set tensile strength extends around the plasticshearing link and is incorporated within the plastic shearing link.According to that patent's specification, the wire is designed to breakonce the life raft is opened and inflated to allow the life raft tofloat to the surface free from the sinking ship. In contrast, thefloat-free link described and claimed herein is believed to besignificantly simpler and easier to manufacture and use than thebreakable device generally described in U.S. Pat. No. 7,302,739.

FIG. 1 is an illustration of a hydrostatic release unit, according to anexample embodiment of the invention. The example hydrostatic releaseunit 10 may include a hydrostatic release mechanism 12, a tether 20,e.g., a strong double-looped rope, cord, cable, line or other fastener,that may be used to attach the mechanism and the safety equipment to avessel deck, rail or other attachment point, and a float-free link 30 asshown in FIG. 1. The hydrostatic release mechanism 12 may be of the kindthat is described and claimed in U.S. Pat. No. 6,878,024 to Kohuth,filed Apr. 12, 2005.

FIG. 2 is a perspective drawing of an example float-free link, accordingto an example embodiment of the invention. FIG. 3 is an end view of thefloat-free link of FIG. 2. The float-free link 30 may be an integrallyformed unit, molded as a single piece. A polycarbonate material that issubstantially stable to ultraviolet light may be injection molded toform the float-free link 30. The polycarbonate material may be made ofany desired color. One possible material for use in making thefloat-free link 30 is the Makroblend UT-403 made by Bayer. This materialis both stable to light and stable to weather, making it suitable foruse in maritime applications where the emergency equipment such as thelife raft may be exposed to the elements for years without being put touse. It will appreciated that other alternative materials, for example,UV resistant nylon or metal with a corrosion proof coating, may also beused to form the link. Of course, for safety reasons, the hydrostaticrelease unit or any of its components should be inspected and replacedas needed.

As more clearly shown in FIG. 2, the example float-free link 30 may bepartially toroidal in shape and includes both a thick hollow tubularbody 32 having closed ends 34 and 36, wherein the tubular body may becurved, and a thin breakaway bridge 38. The first and second ends 34 and36 of the tubular body 32 may be fairly close to but separated from eachother. As can be seen in FIGS. 2 and 3, the tubular body 32 may also bepartially open along its length to permit the tether 20 to be easilythreaded into the channel 40 of the tubular body.

The breakaway bridge 38 may connect the first and second ends 34 and 36of the tubular body. The breakaway bridge 38 may preferably be curved toeliminate corner stress points which could cause premature breaking ofthe breakaway bridge. The bridge 38 may be sized, based on the physicalproperties of the materials from which it is manufactured, to break, ata given temperature range, between a minimum and a maximum forceresulting from strain caused by the first external fastener (e.g., apainter line attached to a buoyant object that has been submerged) oncethe tether has been severed by the hydrostatic release mechanism. Toachieve breakage in the link 30 at the breakaway bridge and not along aportion of the tubular body, the breakaway bridge 38 may be configuredto have a tensile strength that is substantially lower than the tensilestrength of the tubular body of the link. This may be achieved, forexample, by configuring the breakaway bridge to have a substantiallyreduced cross-section as compared to that of the tubular body 32. Thebreakaway bridge 38 may be dimensioned so that it only breaks afterpredetermined minimum desired breaking force has been exceeded andbefore a predetermined maximum desired breaking force has been exceeded.It is advantageous for the breakaway bridge to be located in a differentportion of the device than the location where the tether is attached tothe link, so e.g., the breakaway bridge may be on one end of the devicewhile the tubular channel is located on the opposite end. This allowsbetter control of the breaking strength of the breakaway bridge and mayhelp reduce problems with fouling.

The desired breaking range of the breakaway bridge may be dependent uponthe particular application of the float-free link. For example, undercurrent regulations, the minimum force is about 100 lbs and the maximumforce is about 134 lbs for links intended to be used with life floatsand other buoyant crafts of 10 persons or less capacity. For linksintended to be used for life floats and other buoyant crafts of 11 to 20persons capacity, the breaking range is between about 200 lbs and about268 lbs. The specified range is from about 400 lbs to about 536 lbs forlinks intended to be used with life floats and other buoyant crafts ofmore than 20 persons capacity. See 46 C.F.R. §160.073. In one exampleembodiment, the example breakaway bridge 38 is designed to break atabout 490±60 lbs within an operating temperature range between 150° F.to −22° F. That example embodiment, manufactured with Makroblend UT-403,had a bridge span of about 0.6 inch, a width of about 0.4 inch, athickness of about 0.116 inch, and a radius of curvature of about 0.365inches.

As shown in FIGS. 1-2, the float-free link 30 further includes across-bar 42 bisecting the link to create two apertures 44 and 46. Thecross-bar 42 may be integrally formed within the link 30, e.g., duringthe injection molding process. The first aperture 44 is at the bottom 50of the link 30, to be used with an external fastener, e.g., a shackle,to tie the link 30 to a vessel or a sturdy attachment point on thevessel deck. A portion of the tether 20 that is located inside thechannel 40 of the tubular body of the link 30 is part of the connectionwith the vessel deck. The first aperture 44 is preferably circular todistribute evenly the strain caused by the fastener when the fastener istaut. The second aperture 46 is at the top 52 of the link 30, to be usedto secure the link to a painter line of the life raft. A shackle may beused to mechanically couple the painter line to the float-free link 30.The aperture 46 may be elongated and narrower at the top end 52 of thelink in the area of the breakaway bridge 38. This design facilitates thecorrect positioning of the external fastener from the painter at thebreakaway bridge 38 when the painter is taut. The tether 20 is not apart of the connection to the painter line as the painter line must beable to break away from the vessel if the vessel sinks. The top end 54of the tether 20 is attached to the life raft lashing. The hydrostaticrelease mechanism 12 is attached to tether 20 at a location along thelength of the tether that is not contained within the channel 40 of thetubular body.

FIG. 4 is a perspective drawing of a second example float-free link,according to another example embodiment of the invention. FIG. 5 is across-sectional view of the float-free link of FIG. 4. Similar to thepreviously discussed example embodiment, the float-free link 30′ may bean integrally formed unit, molded as a single piece, from a suitablematerial that is substantially stable to ultraviolet light and weather,and having desired tensile strength characteristics. In this exampleembodiment, the example breakaway bridge 38′ is designed to break atabout 490±60 lbs within an operating temperature range between 150° F.to −22° F. Manufactured with Makroblend UT-403, the breakaway bridge 38′has a bridge span of about 0.4 inches, a width of about 0.74 inch, athickness of about 0.116 inch, a radius of curvature of about 0.27 inch.The thickness must be tightly controlled to insure that the bridge hasthe proper breaking strength. The float-free link 30′ may be configuredwith a single loop and thus a single aperture 44′ in this exampleembodiment. The partially tubular body 32′ of the float-free link 30′may be curved to form part of the closed loop. The breakaway bridge 38′connects the two ends 34′ and 36′ of the body 32′. Again, the body 32′may also be partially open along its length, wherein the channel 40′ isconfigured to permit a tether to be easily coupled to the float-freelink 30′. In this example embodiment, all external fasteners, e.g.,shackles, for mechanically coupling the float-free link to an emergencydevice and to the vessel, may be attached through the aperture 44′.

FIG. 6 is a perspective drawing of a third float-free link 30″,according to yet another example embodiment of the invention. FIG. 7 isa top view of the float-free link 30″ of FIG. 6. Again, the float-freelink 30″ may be an integrally formed unit, molded as a single piece,from a suitable material, such as Makroblend UT-403 or other appropriatepolycarbonates. Similar to the float-free link 30′ as illustrated inFIGS. 4 & 5, the float-free link 30″ may be configured with a singleloop and thus a single aperture 44″ in this example embodiment. Thepartially tubular body 32″ of the float-free link 30″ may be curved intoapproximately a semi-circle and may have tubular channels 40″ similar tothose described in the earlier embodiments. The breakaway bridge 38″ maybe integrally coupled to the body 32″ via a connector 60. The connector60 may be a full closed loop or a partial loop that is integrally formedwith the body 32″ as long as, collectively, the float-free link 30″contains a complete loop to facilitate the attachment of externalfasteners.

In operation, a life raft or other safety equipment may be secured to avessel by an example embodiment of the present invention, in the mannerdepicted in FIG. 8. A lifeboat 80 or other piece of emergency equipmentmay be secured to a mounting 86 or other strongpoint or deck attachmenton a vessel. A link 30, as described previously, may be secured to themounting 86, e.g., with a lashing 84. It will be appreciated that thealternative links described previously may also be used. The lifeboatmay secured to the link in two ways, via a painter line 82 which may beattached to the upper aperture of the link 30 using an optional shackle,and via a tether 20. The hydrostatic release mechanism 12 is positionedso that it can sever the tether 20 when submerged. While the lashing 84and tether 20 are shown directly attached to the link 30, shackles orother forms of indirect attachment could also be employed.

If the vessel sinks, the hydrostatic release mechanism will be activatedat a certain predefined depth, such as 4 meters or less, to sever thetether. The tether connection between the vessel deck and the life raft(or other safety equipment) breaks and the life raft begins to float tothe surface. However, the life raft is still coupled to the vessel viathe painter line that is connected to the top aperture in the link 30.At a certain predefined depth, dependent upon the length of the painterline, the painter line will also become taut which then engages themechanism to open and inflate the life raft. Moreover, the elongation ofthe aperture 46 with its narrower end at the breakaway bridge 38 causesthe fastener from the painter line to position itself naturally at thebreakaway bridge 38. Thus, the force of the taut painter line willstrain the breakaway bridge. The breakaway bridge will break once itstensile strength has been exceeded. Importantly, the breakaway bridgeshould break neither too soon nor too late, and therefore should bedesigned to break only between a minimum and a maximum force within anexpected temperature range, such as between 150° F. and −22° F. Theminimum and maximum forces will be dependent upon the applicableregulations and the size of the life raft as discussed previously. Ifthe breakaway bridge breaks prematurely, then the painter line will nothave engaged the raft-inflating mechanism. If the breakaway bridge doesnot break at a maximum force, then the life raft will not break awayfrom the submerged vessel and cannot float freely to the surface.

One advantage of some of the example embodiments described herein isthat the float-free link 30 may be a unitary integrally moldedstructure. There are no parts to assemble, and therefore there is norisk of mis-assembly or components accidentally coming apart during use.Another advantage is that the example float-free link described hereinis simple to use and can be combined with many forms of releasemechanism and fasteners. Yet another advantage is that the link isdesigned to break at specific location, e.g., at the breakaway bridge,to avoid undesirable breakage in any other part of the link.

It will be appreciated that in an alternative example embodiment, thetether with the hydrostatic release mechanism may be physically separateand apart from the shackles or other connectors attached to thefloat-free link. In such an embodiment, it will be appreciated that thefloat-free link need not have a channel or other component for receivingthe tether.

Although the foregoing specific details describe certain embodiments ofthe present invention, persons reasonably skilled in the art willrecognize that various changes may be made in the details of thisinvention without departing from the spirit and scope of the inventionas defined in the appended claims and considering the doctrine ofequivalents. For example, although certain materials were described asbeing suitable for use in implementing the example embodiments describedabove, it will be readily appreciated that other materials may be used.The float-free link is not limited to being made from polycarbonate butmay be made from other lightweight but weather durable materials withappropriate physical properties. Moreover, the specific dimensions ofthe breakaway bridge may be varied depending upon the physicalproperties of the materials used as well as the desired breaking forcerange. For example, lower tensile strength materials may require largerbreakaway bridges, while lower desired breaking force ranges (forsmaller or lighter weight emergency equipment) may require smallerbreakaway bridges. Additionally, other types of attachments may be usedin place of the tether 20. Also, the tubular body and the breakawaybridge need not be made from the same material but may be of differentmaterials as long as both portions to the float-free link can beintegrally formed. Moreover, two separate links may be coupled togetherto form the float-free link as long as one of the links has thebreakaway bridge. Furthermore, any type of suitable hydrostatic releasemechanism may be used in conjunction with the float-free link and tetherto form a hydrostatic release unit. Other modifications andsubstitutions will also be readily ascertained by persons of ordinaryskill in the art. Therefore, it should be understood that this inventionis not to be limited to the specific details shown and described herein.

1.-43. (canceled)
 44. A float-free link, comprising: a first linkagemeans for allowing a first fastener to be attached thereto; threadingmeans for allowing a second fastener to be threaded through a portion ofthe linkage means; and breakaway means for controlled breaking of thefloat-free link between a minimum and a maximum force and at a specificlocation on the float-free link.
 45. The float-free link of claim 44,further comprising second linkage means for allowing a third fastener tobe attached thereto, wherein the second linkage means is integrallycoupled to the first linkage means.
 46. The float-free link of claim 45,wherein the first linkage means and the second linkage means form aunitary integrally molded structure.
 47. The float-free link of claim44, wherein the first linkage means, threading means, and breakawaymeans form a unitary integrally molded structure.
 48. The float-freelink of claim 47 being composed of a plastic material that issubstantially stable to ultraviolet light
 49. The float-free link ofclaim 48 wherein the plastic material is polycarbonate.
 50. Thefloat-free link of claim 44, wherein the minimum force is at least about100 lbs and the maximum force is no more than about 134 lbs.
 51. Thefloat-free link of claim 44, wherein the minimum force is at least about200 lbs and the maximum force is no more than about 268 lbs.
 52. Thefloat-free link of claim 44, wherein the minimum force is at least about400 lbs and the maximum force is no more than about 536 lbs.
 53. Ahydrostatically-releasable device for fastening an emergency device to avessel comprising: a tether configured to mechanically couple theemergency device to the vessel; a hydrostatic release mechanism attachedto the tether, the hydrostatic release mechanism configured to sever thetether when the hydrostatic release mechanism is submerged below apredetermined depth; a first external fastener mechanically coupled tothe vessel; a second external fastener mechanically coupled to theemergency device; and an integrally formed float-free link having acurved link body having at least one aperture configured to mechanicallycouple the float-free link to the first external fastener, and a channelextending around at least a portion of the at least one aperture, saidchannel configured to receive a portion of the tether threadedtherethrough; and a breakaway bridge integrally formed with the curvedlink body to form a closed loop, wherein the breakaway bridge isdesigned to break between a minimum and a maximum force resulting fromstrain exerted by the second external fastener once the tether has beensevered by the hydrostatic release mechanism.
 54. Thehydrostatically-releasable device of claim 53, wherein the curved linkbody is partially a hollow tubular body which forms the channel throughwhich the tether is threaded.
 55. The hydrostatically-releasable deviceof claim 54, wherein the hollow tubular body is partially open along itslength.
 56. The hydrostatically-releasable device of claim 55, whereinthe hollow tubular body is partially toroidal in shape.
 57. Thehydrostatically-releasable device of claim 53, wherein the breakawaybridge has a tensile strength substantially lower than that of the firstor second link.
 58. The hydrostatically-releasable device of claim 57,wherein the breakaway bridge has a substantially reduced cross-sectionas compared to that of the first or second link.
 59. Thehydrostatically-releasable device of claim 53 wherein the breakawaybridge is dimensioned only to break after the minimum force has beenexceeded and before the maximum force has been exceeded.
 60. Thehydrostatically-releasable device of claim 59, wherein the minimum forceis substantially within a first range of about 100 lbs to 400 lbs andthe maximum force is substantially within a second range of about 134lbs to 536 lbs, and wherein the minimum force is less than the maximumforce.
 61. The hydrostatically-releasable device of claim 59, whereinthe minimum force is at least about 100 lbs and the maximum force is nomore than about 134 lbs.
 62. The hydrostatically-releasable device ofclaim 59, wherein the minimum force is at least about 200 lbs and themaximum force is no more than about 268 lbs.
 63. Thehydrostatically-releasable device of claim 59, wherein the minimum forceis at least about 400 lbs and the maximum force is no more than about536 lbs.
 64. The hydrostatically-releasable device of claim 53, whereinthe tether is a rope.
 65. The hydrostatically-releasable device of claim53, wherein hydrostatic release mechanism is attached to the tether at apoint along the tether that is outside of the channel of the float-freelink.
 66. The hydrostatically-releasable device of claim 53, wherein thecurved link body has a cross-bar to divide the aperture into firstaperture and second aperture, wherein the first aperture is configuredto mechanically couple with the first external fastener and wherein thesecond aperture is configured to mechanically couple with the secondexternal fastener.
 67. A hydrostatically-releasable device for fasteningan emergency device to a vessel comprising: a tether configured tomechanically couple the emergency device to the vessel; a hydrostaticrelease mechanism attached to the tether, the hydrostatic releasemechanism configured to sever the tether when the hydrostatic releasemechanism is submerged below a predetermined depth; and a first externalfastener mechanically coupled to the vessel; a second external fastenermechanically coupled to the emergency device; and an integrally formedfloat-free link having linkage means for allowing the first externalfastener to be mechanically coupled thereto; threading means forallowing the tether to be threaded through a portion of the linkagemeans; and breakaway means for controlled breaking of the float-freelink at a specific location on the float-free link and between a minimumforce and a maximum force resulting from strain caused by the secondexternal fastener once the tether has been severed by the hydrostaticrelease mechanism.